hey Mike, I tried swapping the ports with no real change in performance. It seems that when I manage to get the notches to thier respective frequencies (i.e high side with a low notch and low side with a high notch) the pass portion is more like mountain ranges than a nice flat top. I have a set of used sinclair bp/r filters that I can try, just not sure of frequency.
Thanks. On Thu, 2008-06-19 at 14:15 -0400, [EMAIL PROTECTED] wrote: > The "10 dB" of pass loss is indicative of the RX and TX ports are > "swapped". Depending on what the duplexer was intended to connect to, > ignore the RX/TX labeling and think of the ports as HIGH and LOW. Look > at the rx/tx frequencies on the main label to let you know which is > high and low. > > Best of luck, > Mike/W5JR > > ---[Original Message]--- > From: [EMAIL PROTECTED] > To: [email protected] > Sent: Jun 19, 2008 2:04:15 PM > Subject: Re: [Repeater-Builder] 633-6a-2n notch duplexer > > Dave, > > I've tuned a number of these 633s and had no problems. They are pretty > much notch only with wide pass. Often get over 90 db notch with > little, less than 1 db, insertion loss. > > I would think you have some internal problem, maybe from lightning. > > Wish I could help more. > > 73, ron, n9ee/r > > >From: catdoogan1969 <[EMAIL PROTECTED]> > >Date: 2008/06/18 Wed AM 01:54:08 EDT > >To: [email protected] > >Subject: [Repeater-Builder] 633-6a-2n notch duplexer > > > > >hey guys, > > > >I've got my hands on a GR1225 repeater with an RFE4000a (Celwave > >633-2a-2n) notch duplexer and a phone patch. > > > >The repeater had some questionable solder problems on the output of > >the final due very likely to the poorly tuned duplexer. The solder > >was a quick fix and repeater has a healthy 30 watt output with clean > >rx (opening about .25uV). > > > >My current problem is the tuning of this duplexer, I started out with > >decent rx at the dx antenna input but no tx power was passing. > >Checked with watt meter at the tx port and had full reflect. Tried > >retuning tx side and lost rx sens. I can't seem to get either the rx > >or tx lined up now. I can get the notches placed right but the pass > >portion does not get much higher than -10dB (incoming set to 0dB) > >usually lower. > > > >Is there a start from scratch tuning procedure on these? I contacted > >celwave and they gave me a very simple tuning procedure. My problem > >is that I do not know what the original frequencies were on this > >duplexer. The documentation says that these units are good across > >450-470MHz but could there be certain frequencies that they just > don't > >work well at. > > > >I am using an IFR 1900CSA Monitor with a tracking gen and a 50ohm > load > >on the opposite port being tuned. > > > >Any thoughts on what I am doing wrong would be great...I'm starting > to > >think I've over-promised on this unit. > > > >Thanks guys, > > > >Dave > > > > > > Ron Wright, N9EE > 727-376-6575 > MICRO COMPUTER CONCEPTS > Owner 146.64 repeater Tampa Bay, FL > No tone, all are welcome. > > > >
